After a stroke and no memories from his past, Phil encounters Millie who inhabits a desert part of Isle of Lewis. She will shortly entrust him with his deepest secret : they were in love.

In Cold War Moscow, a female spy steals secrets from an idealistic politician – and falls in love with him. Moscow, 1959: Katya (Rebecca Ferguson, Mission Impossible- Rogue Nation, The Girl on the Train, The White Queen), is young, beautiful – and a spy for the Americans. When she and Mischa (Oliver Jackson-Cohen, Emerald City), begin spying on Alexander ( Sam Reid, Anonymous), an idealistic Communist politician, the last thing she expects is to fall in love with him. Her choice between love and duty leads to a nail-biting conclusion that Alexander (Charles Dance, The Imitation Game) can only unravel decades later in 1990s New York. His journey back to the snowbound streets of Moscow uncovers a love triangle and betrayals from those he trusted most.